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<head>
    <meta charset="UTF-8">
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    <title>Document</title>
</head>
<body>
    <!-- 写一个函数 求m-n之间数字的和？ -->
    <script>
        var m=parseInt(prompt("请输入一个数"));
        var n=parseInt(prompt("请输入一个数"));
        function sum(oneN,twoN){
            if(oneN<=twoN){
                var total=-oneN
                for(var i=oneN; i<twoN;i++){
                    total+=i;
                }
                console.log(total)
            }
            if(oneN>=twoN){
                var total=-twoN
                for(var i=twoN; i<oneN;i++){
                    total+=i;
                }
                console.log(total)
            }
        }
        sum(m,n);
    </script>
</body>
</html>